Polymer coatings for brachytherapy devices
Inventors
Kelson, Itzhak • Keisari, Yona • Schmidt, Michael • Berkowitz, Avia
Assignees
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Publication Number
US-12186412-B2
Publication Date
2025-01-07
Expiration Date
Abstract
An apparatus includes a support, including an outer surface and configured for insertion into a body of a subject. The apparatus further includes multiple atoms of a radionuclide, which radioactively decays to produce a daughter radionuclide, coupled to the outer surface, and a layer of a polymer, which covers the atoms so as to protect the atoms from being washed away, yet allows diffusion of the daughter radionuclide through the layer. Other embodiments are also described.
Core Innovation
The invention relates to brachytherapy devices that include a support configured for insertion into a body of a subject and carrying multiple atoms of an alpha-emitting radionuclide coupled to an outer surface. The radionuclide radioactively decays to produce a daughter radionuclide, and nuclei of the daughter radionuclide diffuse out from within the source to deliver an alpha dose in and/or near a tumor. A polymer layer covers the multiple atoms of the radionuclide to protect the radionuclide atoms from being washed away by body fluids while remaining permeable to diffusion of the daughter radionuclide through the polymer.
The polymer layer has a thickness of at least 0.1 micron, with single and double polymer layer configurations described. The layer is permeable so that daughter radionuclide nuclei diffuse through and out from the layer during use, and diffusion through the polymer is supported by a diffusion coefficient requirement. Radionuclide and support parameters, including radionuclide atom density and support geometry, are selected to support diffusion-driven delivery.
The document also describes manufacturing and physical performance of the coated radiation source. Polymer layers can be applied using dip-coating, and in double-layer embodiments the inner and outer polymer layers are formed to be compatible with subsequent coating steps. Experimental results indicate no radium loss and improved radon desorption probabilities, including a comparison between single-layer and double-layer configurations.
Claims Coverage
The independent claims cover an apparatus, a method of preparing a polymer-covered alpha-emitting radionuclide source, and a method of using the resulting radiation source by inserting it into a body such that daughter radionuclide nuclei diffuse through the polymer. Across the independent claims, the core inventive structure is an alpha-emitting radionuclide on an insertable support with a polymer layer of at least 0.1 micron that prevents wash-off while allowing diffusion of the daughter radionuclide.
Alpha-emitting radionuclide on insertable support with polymer diffusion layer
A support configured for insertion into a body of a subject, multiple atoms of an alpha-emitting radionuclide coupled to the outer surface where the radionuclide radioactively decays to produce a daughter radionuclide, and a layer of a polymer having a thickness of at least 0.1 micron that covers the multiple atoms to protect them from being washed away by body fluids and allows diffusion of the daughter radionuclide through the layer.
Sequential coupling and polymer covering of radionuclide on outer surface
Coupling multiple atoms of an alpha-emitting radionuclide that radioactively decays to produce a daughter radionuclide to an outer surface of a support configured for insertion into a body of a subject, and subsequently covering the coupled multiple atoms with a layer of a polymer having a thickness of at least 0.1 micron that protects the radionuclide atoms from being washed away by body fluids and allows diffusion of the daughter radionuclide through the layer.
In-body insertion and diffusion-driven daughter radionuclide release
Inserting a radiation source into a body of a subject, where the radiation source comprises a support including an outer surface, multiple atoms of an alpha-emitting radionuclide coupled to the outer surface where the radionuclide radioactively decays to produce a daughter radionuclide, and a layer of a polymer having a thickness of at least 0.1 micron that covers the multiple atoms to protect them from being washed away by body fluids and allows diffusion of the daughter radionuclide through the layer; leaving the radiation source within the body such that nuclei of the daughter radionuclide diffuse through the layer of the polymer.
Across the independent claims, the coverage centers on a polymer-covered alpha-emitting radionuclide source on an insertable support, where the polymer layer at least 0.1 micron thick protects radionuclide atoms from wash-off by body fluids while allowing diffusion of daughter radionuclide nuclei, including an insertion and retention use step that relies on in-body diffusion through the polymer.
Stated Advantages
Protects the multiple atoms of the radionuclide from being washed away by body fluids while allowing diffusion of the daughter radionuclide through the polymer.
No radium loss is reported in experimental results.
Improved radon desorption probability is reported, including higher probability for a double-layer configuration compared with a single-layer configuration.
Documented Applications
Brachytherapy, including delivering an alpha dose in or near a tumor by leaving a polymer-covered alpha-emitting radionuclide radiation source within the body so that daughter radionuclide nuclei diffuse through the polymer.
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